Crystal Characterizing was the first thing I tried as a virgin VNA owner.
Even before reading the manual, navigated the menu tree provided on a paper sheet.
I was trying to characterize 12.2 MHz crystal, especially wanting its internal resistance at resonance, a difficult parameter to measure. G3UUR was used to get Lm, Cm parameters (G3UUR doesn't do Rm well). I had measured Rm tediously using other instrumentation... 7 or 8 ohms. Then moved the crystal to VNA....

Under MEASURE menu, an item is available called RESONANCE - select that.
Then move to STIMULUS menu, choosing CENTER.
Use the on-screen numeric keypad punching in 12.2 M (for my example 12.2 MHz crystal)
Then, still under STIMULUS menu, choose SPAN of perhaps 20k...that's a wide sweep but you can narrow it later once you've found resonance. A crystal's series resonance is very often below the printed value.
I just touch the crystal into the VNA's S11 port's SMA connector and wait for the display to settle.
On-screen, series-resonant frequency is displayed, along with Rm resistance (plus a bit of reactance that jiggles near zero).
For my 12.2 MHz crystal, Rm displayed was 7 ohms, verifying my previous measurement.

You can now refine the sweep:
Under STIMULUS/CENTER, re-punch in the refined series-resonant frequency found above.
Then, under STIMULUS/SPAN, set a smaller sweep, maybe 5k, or even less. Re-measure the crystal

As a first-time experience with VNA, I was very impressed!